The CAD model is courtesy of GrabCAD member Ned Kralev. The file has been modified so that it could be uploaded as a STEP-file consisting out of a single solid. For the mesh generation we apply a manual snappyHexMesh operation with refined boundary layers near the submarine walls and defined boundary boxes for a more detailed simulation in the region around the submarine. The resulting mesh consists out of around 1.400.000 cells. A cut view of one of the meshes is shown in the figure below.
The simulation has been set up applying a constant velocity of 15m/s at the inlet, a zero-gradient boundary condition at the outlets and a symmetry plane to all other sides of the boundary box. The steady-state simulation took around 28 minutes on a 16-core-machine. The results are shown in the figures below.
The first one shows the velocity in a 2D-Visualisation.
This figure visualizes the velocity as stream lines around the submarine.
The last figure shows the development of the turbulent kinetic energy.